ABSTRACT
Objective To characterize a species of the genus Tricula and parasitized trematodes in schistosomiasis-endemic areas of Yunnan Province using a molecular analysis, so as to understand their taxonomic positions. Methods Tricula spp. and Oncomelania snails were collected from Xiangyun County, Yunnan Province, and cercaria parasitizing snails were observed using crushing followed by microscopy. Cercaria parasitizing Tricula snails at various morphologies were sampled using a shedding method. Genomic DNA was extracted from snail soft tissues and cercariae, and the 16S rRNA, COI, 28S rDNA genes in snails and the ND1 and 28S rDNA genes in cercariae were amplified using a PCR assay and sequenced. The species of Tricula snails and their parasitized trematodes was characterized using sequence alignment and phylogenetic analysis. Results Among 382 Tricula snails detected, there were three types of trematode cercariae found, including the non-forked (20.94%, 80/382), double-forked (3.40%, 13/382) and swallow shapes (7.07%, 27/382). Sequence and phylogenetic analyses showed that the 16S rRNA, COI and 28S rDNA gene sequences of this species of Tricula had high homology to those in Delavaya dianchiensis, and were clustered in a branch. Sequencing analysis of the ND1 and 28S rDNA genes revealed that the non-forked cercariae belonged to the family Pleu- rogenidae, the swallow-shaped cercariae belonged to the family Opecoelidae, and the double-forked cercariae belonged to another species of the genus Schistosoma that was different from S. sinensium and S. ovuncatum. Conclusion The species and taxonomy of Triculla spp. and their parasitized trematodes are preliminarily determined in schistosomiasis-endemic areas of Yunnan Province; however, further studies are required to investigate the more definite taxonomy and pathogenicity.
ABSTRACT
Objective To evaluate the potential risk of schistosomiasis transmission so as to provide the evidence for formulating the control strategy. Methods Two villages were selected as the investigated sites in Chuxiong City and the risk of schistosomiasis transmission was evaluated by reviewing the data of schistosomiasis epidemic situation and prevention and control work, and carrying out the field survey for Oncomelania hupensis snail status, wild faeces, and schistosome infection of the population from 2015 to 2017. Results There was 1.49 hm2 area of snail habitats, with an average density of 0.54 snails/0.1 m2. The occurrence rate of frames with snails was 5.41%. No schistosome-infected snails were found. The positive rate of schistosomiasis serological tests of the residents was 3.36%, but the stool examination positive cases were not found. A total of 58 wild faeces samples were collected but no schistosome infested cases were found. The risk levels of schistosomiasis transmission in both villages were Grade III. Conclusions Although Chuxiong City has been in a low risk state of schistosomiasis transmission, the density of snails is still high, and there is a risk of infection source importation. In the future, the infection source control and snail control should be strengthened.
ABSTRACT
A three-level (provincial, municipal and county levels) schistosomiasis diagnosis network platform had been created in Yunnan Province, and assessment of laboratory quality-control samples and field evaluation of nucleic acid diagnostic techniques and immunodiagnostic reagents had been performed. This paper described the review process of the schistosomiasis diagnosis network laboratory and the operation of schistosomiasis diagnosis network laboratory and analyzed the problems of the schistosomiasis diagnosis network laboratory in Yunnan Province. The establishment of the schistosomiasis diagnosis reference (network) laboratory will provide a strong support for schistosomiasis control in Yunnan Province in the new era.
ABSTRACT
Objective To assess the effectiveness of infectious source control at various stages of transmission control of schistosomiasis in Eryuan County of Yunnan Province, so as to provide insights into the further monitoring and management of infectious sources of schistosomiasis. Methods Wenbi Village, a plateau subtype region and Qiandian Village, a mountain subtype region in Eryuan County were selected as the study areas. The species, schistosome infection and transmission capability of infectious sources were investigated in Wenbi and Qiandian villages in 2011 and 2018 and were compared. Results Schistosome infections were detected in human, bovine, horse, dog and mouse in Qiandian Village in 2011, with positive rates of 1.19%, 0.91%, 1.25%, 3.13% and 0.95%, respectively, and human, bovine and dog were found to have schistosome infections, with positive rates of 0.76%, 1.66% and 9.30%, respectively. However, no infections were identified in human, bovine, horse, pig, dog, sheep or mouse in these two villages in 2018. A total of 731 wild feces were collected in both villages in 2011. In Qiandian Village, horse, bovine and dog feces accounted for 34.40%, 29.80% and 20.20% of all fecal samples, and dog and horse feces were found to have schistosome infections (11.94% and 6.90% positive rates, respectively). In Wenbi Village, dog, bovine and human feces accounted for 44.59%, 39.83% and 14.29% of all fecal samples, and dog, human and bovine feces were found to have schistosome infections (16.95%, 9.52% and 2.33% positive rates, respectively). In 2018, a total of 204 wild feces were collected in both villages, and no schistosome infections were identified. Sheep, dog and bovine feces accounted for 36.27%, 33.33% and 27.45% of all fecal samples in Qiandian Village, and dog, bovine and human feces accounted for 72.55%, 11.76% and 10.78% of all fecal samples in Wenbi Village. Conclusions A remarkable achievement has been obtained in the control of infectious sources of schistosomiasis in Eryuan County, and the role of human and bovine as the major infectious sources of schistosomiasis has been effectively controlled. In the future, the integrated strategy with emphasis on the control of infectious sources should be intensified, and the management of reservoir hosts including dog and mouse should be strengthened.
ABSTRACT
Objective To evaluate the potential risk of schistosomiasis transmission so as to provide the evidence for formulating the control strategy. Methods Two villages were selected as the investigated sites in Chuxiong City and the risk of schistosomiasis transmission was evaluated by reviewing the data of schistosomiasis epidemic situation and prevention and control work, and carrying out the field survey for Oncomelania hupensis snail status, wild faeces, and schistosome infection of the population from 2015 to 2017. Results There was 1.49 hm2 area of snail habitats, with an average density of 0.54 snails/0.1 m2. The occurrence rate of frames with snails was 5.41%. No schistosome-infected snails were found. The positive rate of schistosomiasis serological tests of the residents was 3.36%, but the stool examination positive cases were not found. A total of 58 wild faeces samples were collected but no schistosome infested cases were found. The risk levels of schistosomiasis transmission in both villages were Grade III. Conclusions Although Chuxiong City has been in a low risk state of schistosomiasis transmission, the density of snails is still high, and there is a risk of infection source importation. In the future, the infection source control and snail control should be strengthened.
ABSTRACT
A three-level (provincial, municipal and county levels) schistosomiasis diagnosis network platform had been created in Yunnan Province, and assessment of laboratory quality-control samples and field evaluation of nucleic acid diagnostic techniques and immunodiagnostic reagents had been performed. This paper described the review process of the schistosomiasis diagnosis network laboratory and the operation of schistosomiasis diagnosis network laboratory and analyzed the problems of the schistosomiasis diagnosis network laboratory in Yunnan Province. The establishment of the schistosomiasis diagnosis reference (network) laboratory will provide a strong support for schistosomiasis control in Yunnan Province in the new era.
ABSTRACT
Objective To assess the effectiveness of infectious source control at various stages of transmission control of schistosomiasis in Eryuan County of Yunnan Province, so as to provide insights into the further monitoring and management of infectious sources of schistosomiasis. Methods Wenbi Village, a plateau subtype region and Qiandian Village, a mountain subtype region in Eryuan County were selected as the study areas. The species, schistosome infection and transmission capability of infectious sources were investigated in Wenbi and Qiandian villages in 2011 and 2018 and were compared. Results Schistosome infections were detected in human, bovine, horse, dog and mouse in Qiandian Village in 2011, with positive rates of 1.19%, 0.91%, 1.25%, 3.13% and 0.95%, respectively, and human, bovine and dog were found to have schistosome infections, with positive rates of 0.76%, 1.66% and 9.30%, respectively. However, no infections were identified in human, bovine, horse, pig, dog, sheep or mouse in these two villages in 2018. A total of 731 wild feces were collected in both villages in 2011. In Qiandian Village, horse, bovine and dog feces accounted for 34.40%, 29.80% and 20.20% of all fecal samples, and dog and horse feces were found to have schistosome infections (11.94% and 6.90% positive rates, respectively). In Wenbi Village, dog, bovine and human feces accounted for 44.59%, 39.83% and 14.29% of all fecal samples, and dog, human and bovine feces were found to have schistosome infections (16.95%, 9.52% and 2.33% positive rates, respectively). In 2018, a total of 204 wild feces were collected in both villages, and no schistosome infections were identified. Sheep, dog and bovine feces accounted for 36.27%, 33.33% and 27.45% of all fecal samples in Qiandian Village, and dog, bovine and human feces accounted for 72.55%, 11.76% and 10.78% of all fecal samples in Wenbi Village. Conclusions A remarkable achievement has been obtained in the control of infectious sources of schistosomiasis in Eryuan County, and the role of human and bovine as the major infectious sources of schistosomiasis has been effectively controlled. In the future, the integrated strategy with emphasis on the control of infectious sources should be intensified, and the management of reservoir hosts including dog and mouse should be strengthened.